Hi,
I haven't had any experience with tire balls but I have been running the Tubliss system for well over two years now with no problems. The high pressure in the "inner tube" needs to be monitored as it has a small volume and it doesn't take too many molecules to pass to lower the pressure. I found that using a high quality metal valve stem cap helps to slow the deflation. Mine will drop from 110 to 90 in about a week or ten days. Even at 80 or 90 psi in the inner tube the Tubliss system is effective. I also found that if using a tube type tire installing some Slime seems to take the place of a tubeless tire's air holding inner liner.
I am presently running a Pirelli MT43 rear at 5-6 psi and a Scorpion Pro front at 10 psi. The MT43's traction is remarkable, much better than the Scorpion Pro I used to run in the rear at the same pressures. I don't know how it will wear but it is much more durable than the Michelin X Light Trials which netted me nothing but puncture after puncture and finally a tear that even the slim couldn't breach. I rode an entire "hero" section at the Big Woods 200 with the Michelin completely flat only because of the Tubliss system so if you don't like the balls this would be a great option.
Jim